SOLUTION: ind the center of a circle with the equation x2 + y2 + 2x + 4y – 9 = 0.

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Question 474176: ind the center of a circle with the equation x2 + y2 + 2x + 4y – 9 = 0.
Found 2 solutions by ewatrrr, Tatiana_Stebko:
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

finding the center of a circle with the equation

Note: Standard Form of an Equation of a Circle is %28x-h%29%5E2+%2B+%28y-k%29%5E2+=+r%5E2

where Pt(h,k) is the center and r is the radius



x^2 + y^2 + 2x + 4y – 9 = 0  |completing Squares

 (x+1)^2 -1 + (y + 2)^2 -4  -9 = 0

   (x+1)^2 + (y+2)^2 = 14

    C(-1,-2)

Answer by Tatiana_Stebko(1539) About Me  (Show Source):
You can put this solution on YOUR website!
+x%5E2+%2B+y%5E2+%2B+2x+%2B+4y+-+9+=+0
+%28x%5E2%2B2x%29+%2B+%28y%5E2+%2B+4y%29+-+9+=+0
+%28x%2B1%29%5E2-1+%2B+%28y%2B2%29%5E2-4+-+9+=+0
+%28x%2B1%29%5E2%2B+%28y%2B2%29%5E2+=+14
Point (-1, -2) is a center